Annotate TValue on ConditionalWeakTable.Remove polyfill to fix IL2091

[SimonCropp]

Fixes #615

ConditionalWeakTable<TKey, TValue> declares TValue with [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] (net6.0 through net10.0). The Remove(key, out value) polyfill declared TValue without it, so trim analysis reported IL2091 for any consumer that roots its assembly, even if it never calls Remove.

Changes

• Polyfill_ConditionalWeakTable.cs: annotate TValue to match ConditionalWeakTable. Split copies regenerated.
• ConsumeTrimmed.csproj: add <TrimmerRootAssembly Include="$(AssemblyName)" />. The project previously only trimmed reachable code, and nothing reachable calls Remove, so the trimmer never analyzed it. Rooting the assembly makes it analyze every polyfill.
• assemblySize.include.md: regenerated by ApiBuilderTests.

Verification

• Before the fix, the rooted net9.0 publish of ConsumeTrimmed failed with the IL2091 from the issue, and it was the only trim warning.
• After the fix, the rooted publish (PublishAll) is clean on net7.0 through net11.0.
• Consume compiles on all target frameworks.
• ConditionalWeakTableRemove passes on net48 and net9.0.

Note

CI builds ConsumeTrimmed but does not publish it, so the rooting only catches this class of bug when PublishAll is run. A publish step in build.yml would make it a standing guard; not included here.